German Patent Application No. 35 13 937 describes a method for monitoring a rotation speed sensor signal in which the rotation speed sensor signal is tested not only terms of its presence, but additionally with regard to its plausibility. Plausibility monitoring of the rotation speed sensor signal, which is present as a pulse train, takes place by the fact that on the basis of the rotation speed sensor signal, a time value is determined which describes the time interval between the individual pulses of the current rotation speed sensor signal. Limit values which depend in each case at least on the last rotation speed sensor signal are defined for the current time value. If the current time value exceeds those limit values upward or downward, the monitoring system recognizes that the current rotation speed sensor signal is not reasonable and that a fault in the rotation speed sensor therefore exists. If, on the other hand, the current time value lies within the defined limits, the rotation speed sensor signal is forwarded for further processing.
German Patent Application No. 195 10 525.7 describes a method and an apparatus for controlling or regulating the braking system of a vehicle. With this method and apparatus, brake pedal actuation is sensed by at least two measurement devices, preferably different in nature. In a preferred implementation, for example, the first measurement device senses the distance traveled by the pedal, and the second measurement device senses the actuation force exerted by the driver on the pedal. In an error recognition system provided in the method and the apparatus, the signal representing the pedal travel and the signal representing the pedal force are first tested for plausibility. This is done by comparing the respective signal amplitude or respective signal gradient with a corresponding threshold. If these plausibility comparisons indicate that both sensor signals are plausible, a desired braking force on the vehicle center of gravity that represents the driver's braking input is calculated in each case on the basis of both the signal representing the pedal travel and the signal representing the pedal force. The difference between the two braking force values is compared with a defined threshold. If the difference is less than the defined threshold, it can then be assumed that the system for determining braking input is operating correctly, and that the sensors are also fault-free. If the result, however, is either that the sensor signals are not plausible or that the difference determined from the braking signals is greater than the defined threshold, an examination is made as to which of the two sensors is faulty. This examination is performed with reference to the braking forces determined from the two sensor signals and a reference variable determined from the signal of a third sensor. On the basis of the deviations of the respective braking force from the reference variable, a determination is made as to which of the two sensors is faulty.
Systems for regulating the operating dynamics of a vehicle are known, for example from the publication "FDR--die Fahrdynamikregelung von Bosch", (FDR--the vehicle dynamics regulation system from Bosch) in Automobiltechnische Zeitschrift (ATZ) 96, 1994, Vol. 11, on pages 674-689. This publication also shows that a sensor monitoring system can be implemented by testing, in a model calculation, whether or not the correlations between the signals determined via the vehicle motion are being violated. In addition, this publication shows that the model can also be used to calculate and compensate for the sensor offsets occurring within sensor specifications.
It is the object of the present invention to improve the monitoring of sensors used in a vehicle and the correction of the signals generated by sensors used in a vehicle.